Thats right, for example scios in the the MK14 has code from 0000 that references storage & variables below 0xFFFF by relative addressing, the original cross thought that 0xFFFF was an offset of ~64k above the code so flagged an offset error. It wasnt aware that wrap-around means these variables are actually only a short hop away in the backwards direction
I'm not sure why San hasnt updated his website, seems odd, yet he's happy to send anyone the update if they email him.
The update seems solid, I've used it on scios, nibl, page2 and a few small projects - though I have to constantly refer to the SBASM manual